Optical transmission apparatus having automatic wavelength control function

摘要

The invention concerns an optical transmission apparatus; more particularly, the invention is directed to the provision of an optical transmission apparatus having a high receiver sensitivity wherein a wavelength tunable light source is used as a main signal source in an optical transmitter and the wavelength of the light source is made variable to be able to follow a pass-band wavelength drift of an optical filter. An automatic wavelength control circuit in the optical transmission apparatus comprises: a wavelength detector for monitoring the main signal light from the wavelength tunable light source, and for outputting a level signal proportional to the wavelength of the main signal light by passing the monitor signal light through a prescribed optical filter; and a wavelength controller for varying the wavelength of the main signal light by driving the wavelength tunable light source, and for determining the wavelength of the main signal light from a change in the level signal from the wavelength detector that follows the variation of that wavelength, and thereby setting and holding the wavelength of the main signal light from the wavelength tunable light source at a designated wavelength.